Device for measuring blood, tissue, and skin parameters

ABSTRACT

The invention relates to a device and a method for measuring of blood, tissue, or skin parameters, in particular the oxygen saturation in blood, by attaching to body parts such as fingers, earlobes, toes, hand, or foot. The invention relates further to a method for the preparation of said device.

The invention relates to a device and a method for measuring blood, tissue, or skin parameters, in particular the oxygen saturation in blood, by attaching to body parts such as fingers, earlobes, toes, hand, or foot. The invention further relates to a method for the preparation of said device.

The pulse oximetry via SpO2 sensor technology with non-invasive technique for the continuous measurement of arterial oxygen saturation of the blood has already been well established in patient monitoring. Here, a distinction is made between SpO2 sensors as disposable sensors for the single use and reusable sensors for the repeated use.

An SpO2 disposable sensor is in particular used for the continuous observation, the long-term monitoring, of patients that have to be monitored over several hours, partially over several days regarding its state of health. To this, the SpO2 disposable sensor is applied onto predetermined positions at the body and fixed. After a certain utilization period, as a rule after eight hours, this sensor has to be newly applied to another place of the body. The background to this is to ensure that the sensor does not cause and exercise any negative affects such as pressure, temperature, or allergic reactions on this place of body. In addition, in case of reapplication there is also ensured that the medical skilled person will check the right function of the sensor. An essential advantage of disposable sensors over the reusable sensors is given by their construction and fixation to the human body.

The disposable sensor is characterized by its low mass and by the plaster tape material, which at the same time also presents a cost-effective technical variation. Hereby, motion artifacts and hence measuring errors in the patient monitoring at the SpO2 monitor are reduced or excluded, respectively. These are the essential requirements that are necessary for the employment of sensors with newborns, neonates. For this, as the neonates have to be monitored after their birth with regard to the correct work of the lung over several hours up to 72 hours the employment of an SpO2 disposable sensor is absolutely imperative. A typical application of the SpO2 disposable sensor is the attachment to the hand or foot of a baby. Since the baby is moving all the time during the period of monitoring, a save and strong application of the sensor is necessary. The sensor must not slip off from the site of application, from the foot or from the hand by itself.

Furthermore, it has to be ensured that the SpO2 sensor does not pose a threat to the patient. In this case, there could be caused burns at the baby's skin as well as pressure sores of the sensor by a too tight application or allergic reactions by the adhesive material of the plaster tapes at the skin surface.

Therefore, an international norm does exist, the ISO 9919, for all SpO2 monitors and the corresponding SpO2 sensors. Herein, the exact demands on each sensor, and monitor manufacturer are defined also with respect to the sensor's safety requirements.

From the company DIXTAL Medical Inc. (U.S. Pat. No. 6,073,038; U.S. Pat. No. 6,149,481; U.S. Pat. No. 5,891,026) the construction and employment of a neonate pediatric SpO2 sensor is known. Said sensor is characterized in that it is composed of a foam wrap base material, onto which are fixed by two additional adhesive tapes a cable and the SpO2 optics soldered thereto composing of SpO2 LEDs and a detector. For this, the optics and the cable are fixed between two very thin adhesive tapes, which are arranged on the upper side of the fixing strap. Essential disadvantages of said sensor are

-   -   insufficient fixation of the optics and the cable between the         two thin adhesive tapes, due to which in case of mechanical         stress such as pulling the cable when the sensor is applied,         there is a risk that the cable together with the optics is         pulled out of the disposable sensor;     -   no strain relief by the cable at the sensor, so that in case of         moving the cable it might release between the two adhesive         tapes;     -   insufficient protection of the optics and the electric contacts         such as cable, stranded wires against penetration of liquids in         accordance with the requirements by the norm;     -   the sensor can not sufficiently be fixed at the body, since the         thin adhesive tape which takes up the optics has no sufficient         skid resisting properties to movements;     -   said disposable sensor is not sufficient padded against pressure         sores at the positions where the optics is located, because the         optics is only separated by a very slim tape from the baby's         skin;     -   the electric safety of said sensor regarding contact discharge,         high voltage is not given at a prescribed dielectric strength of         4 kV, since the insulation takes place by only a thin film.

Object of the invention was to provide a device for measuring blood, tissue, or skin parameters, in particular the oxygen saturation in blood, which does not exhibit the mentioned disadvantages and moisture-tight covers over and safely closes with only a few single elements the transmitting and receiving unit, guarantees a high operational reliability also in case of changing stresses as well as an easy attachment to body parts different in size. In addition, by the few single elements the device is intended to be prepared easily and fast and hence cost-effectively.

According to the invention this object is solved by the device according to claim 1. Therefore, the device of the present invention comprises a sensor with a flexible fixing strap with an upper part, a Velcro fastening arranged at the end thereto, and a plastic foam-like, in particular skid resisting lower part, the device being characterized in that between upper part and lower part a transmitting optics and a detector are arranged, and moisture-tight encapsulated with a connecting cable between the two halves of a foldable capsule band which is self-adherent at the inner surfaces.

As the transmitting optics there are used one or more, preferably two common LEDs known to the skilled person which emit light and introduce it to the patient. The detector is used as an optical receiver for the light from the patient.

Preferably, the connecting cable is fastened with a strain relief band at the fixing strap. For this, for example the connecting cable is wrapped with the strain relief band, the strain relief band being connected tension-proof with the transmitting optics and detector via the fixing strap. In one embodiment the strain relief band is a self-adherent film wrapping a part of the fixing strap as well as the connecting cable.

In a further embodiment the upper part of the device according to the invention is formed tension-proof and connected Velcro-like with the plastic foam-like lower part. Alternatively, the upper part may be formed tension-proof and connected in a self-adherent way with the plastic foam-like lower part.

The device in accordance to the invention preferably has windows in the area of transmitting optics and detector both in the capsule band and in the lower part of the fixing strap, so that the light emitted from the transmitting optics can reach the bodily organ of the patient and from there can come back to the detector. The windows are either just openings or areas that are composed of an optically translucent material.

The outside of the upper part is preferably formed Velcro-like so that it can be connected with the Velcro fastening arranged at the end of the fixing strap. In this way the device can be attached flexible and essentially pressure-free to the desired bodily organ.

In a further embodiment the foldable capsule band of the device according to the invention is composed of a mainly white, moisture-impermeable material, for example a white plastic film.

The present invention relates further to a method for measuring blood, tissue, or skin parameters, in particular the oxygen saturation in blood, which method is characterized in that a device as described above is attached to a body part such as fingers, toes, earlobes, hand, or foot. Then the connecting cable can be connected with a corresponding evaluation unit which for example determines and displays the oxygen saturation in the patient's blood via the light received by the detector.

Due to the only few single elements compared to known sensors of which the device according to the invention is build-up it is possible to prepare it in an easy and fast and hence cost-effective way. For this, at first the sensor unit composed of the LED or LEDs, the detector, and the connecting cable is positioned on one of the halves of the foldable capsule band having a self-adhering inner surface. Subsequently, the mainly self-adhering strain relief band is fixed to the connecting cable and so ensures the strain relief of the sensor unit in case of mechanical stresses. By folding up the second half of the foldable capsule band now the complete sensor unit is adhesively closed moisture-tight.

This covered over sensor unit is now positioned and fixed at the inner surface on the upper part of the fixing strap. After this, the plastic foam-like lower part is connected congruent with the upper part of the fixing strap and the sensor unit, and the strain relief band is fully enclosed around the connecting cable to carry out the strain relief.

The invention is now discussed in detail regarding the example without considering it as limiting.

FIG. 1 shows an opened up view of the sensor

FIG. 2 shows the top view of the sensor

FIG. 3 shows the bottom view of the sensor

FIG. 1 shows the sensor (1) with fixing strap (2) which is formed by the tension-proof upper part (2.1) and the congruent plastic foam-like lower part (2.2) and connects them self-adherent to each other. The upper part (2.1) is formed Velcro-like at the outside and self-adherent at the inside, so that with Velcro fastening (3) a variable length adjustment is ensured when the sensor (1) is attached to a body part such as foot, toe, or hand. Transmitting optics (4) and detector (5) are positioned adhesively on one half of the foldable capsule band (7) with strain relief band (8). After this, the other half of the capsule band (7) is folded and by pressing onto transmitting optics (4) and detector (5) these are covered over moisture-tight. The strain relief band (8) is designed to be self-adherent on one side and is now wrapped around the connecting cable (6) and thus secures the position of transmitting optics (4) and detector (5) at the connecting cable (6) in case of mechanical stresses. The capsule band (7), which herein is white, is preferably designed to be adhesive on both sides so that it covers over transmitting optics (4) and detector (5) self-adherent moisture-tight and is self-adherent arranged between upper part (2.1) and lower part (2.2). In this way, the capsule band (7) acts in addition as strain relief for the transmitting optics (4) and detector (5).

FIG. 2 shows the sensor (1) from the Velcro-like outside of the tension-proof upper part (2.1) at which the Velcro fastening (3) is arranged at the end and to which the Velcro fastening (3) can be connected length-variable in a form-closed fashion.

The connecting cable (6) is wrapped by the self-adherent strain relief band (8) for strain relief and thus ensures the required high operational reliability of the measuring method in case of mechanical stresses of the connecting cable (6) by tensile stresses.

In FIG. 3 there is represented the bottom view of the whole sensor (1) with its plastic foam-like lower part (2.2) that can be padded as well as the windows (2.3) for light of the transmitting and receiving optics. Further there can be seen the folded Velcro fastening (3) as well as the connecting cable (6) with the strain relief band (8) wrapped around for the strain relief of the connecting cable (6) in case of mechanical stresses. 

1. A device for measuring blood, tissue, or skin parameters, including the oxygen saturation in blood, by attaching to bodily organs, said device comprising a sensor (1) having a flexible fixing strap (2) with upper part (2.1), a Velcro fastening (3) arranged thereto at the end, and a plastic foam-like, skid resisting lower part (2.2), characterized in that between upper part (2.1) and lower part (2.2) there is arranged, and encapsulated in a self-adherent moisture-tight configuration a transmitting optics (4) and a detector (5) having a connecting cable (6) between the two halves of a foldable capsule band (7) which is self-adherent at the inner surface with a strain relief band (8).
 2. The device according to claim 1, characterized in that the connecting cable (6) is fixed at the fixing strap (2) with a strain relief band (8).
 3. The device according to claim 1, characterized in that the upper part (2.1) is tension-proof and Velcro-like connected with the plastic foam-like lower part (2.2).
 4. The device according to claim 1, characterized in that the upper part (2.1) is tension-proof and self-adherent connected with the plastic foam-like lower part (2.2).
 5. The device according to claim 1, characterized in that there are windows (2.3) in the area of the transmitting optics (4) and the detector (5) in the capsule band (7) and in the lower part (2.2).
 6. The device according to claim 1, characterized in that the outside of the upper part (2.1) is formed Velcro-like.
 7. The device according to claim 2, characterized in that the strain relief band (8) is wrapped around the connecting cable (6) and is connected tension-proof with the transmitting optics (4) and the detector (5) via the fixing strap (2).
 8. The device according to claim 1, characterized in that the foldable capsule band (7) is composed of a mainly white moisture-impermeable material.
 9. A method for measuring blood, tissue, or skin parameters, in particular the oxygen saturation in blood, characterized in that a device according to claim 1 is attached to a body part such as fingers, toes, earlobes, hand, or foot.
 10. A method for the preparation of a device for measuring blood, tissue, or skin parameters, including the oxygen saturation in blood, by attaching to bodily organs, said method comprising the steps of: a) applying a transmitting optics (4) and a detector (5) having a connecting cable (6) to one half of the foldable capsule band (7) which at the inner surface is self-adherent; b) folding up the two halves of the capsule band (7) to encapsulate the transmitting optics (4) and the detector (5) moisture-tight; c) adhering an outer surface of the capsule band (7) to the inside of the upper part (2.1) having a Velcro fastening (3) attached thereto at the end of a flexible fixing strap (2); d) putting on a plastic foam-like lower part (2.2); and e) connecting the upper part (2.1), connecting cable (6), and lower part (2.2) via a strain relief band (8).
 11. The method according to claim 10, wherein the upper part (2.1) is tension-proof and is Velcro-like connected with the plastic foam-like lower part (2.2).
 12. The method according to claim 10, wherein the upper part (2.1) is tension-proof and is self-adherent connected with the plastic foam-like lower part (2.2).
 13. The method according to claim 10, wherein there are windows (2.3) in the area of the transmitting optics (4) and the detector (5) in the capsule band (7) and the lower part (2.2).
 14. The method according to claim 10, wherein the outside of upper part (2.1) is formed Velcro-like.
 15. The method according to claim 10, wherein the connecting cable (6) is wrapped with strain relief band (8) and is tension-proof connected with the transmitting optics (4) and detector (5) via the fixing strap (2).
 16. The method according to claim 10, wherein the foldable capsule band (7) is composed of a mainly white moisture-impermeable material. 